Mercedes, BMW, VW, Audi, most Porsche and others use mostly Mann as OE,
while (at least some) Mini, Peugeot, Citroen, Ferrari, Maserati and Jaguar use
Purflux as OE. I don't think that does one make any better than the other. The
lack of reliable test data doesn't either. So I'd say you can use them both with
confidence, and just use what you feel most comfortable with. Your engine
most cerainly won't notice what brand oil filter you go for as long it's a quality
part such as Mann or Purflux. I use to run Mann in my GTI while I run Purflux in
my Mini. Currently there's an OE BMW/Mini filter in, but that's actually a Purflux.